Can you help me with the title? The first version is a literal translation.

Please, check the rest of the paragraph. Thank you.

Professional petrol poisoning/Health hazards with petrol/Petrol health hazards?

Although modern refineries are very complex, the production of petrol is well defined and it is undertaken in closed systems of pipes and containers. However, the air in refineries contains low levels of hydrocarbon vapours/fumes, as a result of numerous small leakages and spills. Maximum tolerable limits for petrol exposure are 330 ppm (900mg/m3).
For me the title of this paragraph would be better as 'Health Hazards in Petrol Refineries' but it doesn't look as though that's a translation.

In the paragraph, which is fine, you only need vapour in the singular not pluaral.
Actually, I think that Mister Micawber mentioned before something like occupational health hazards. Perhaps I could say Occupational health hazards with/of petrol. Although this with sounds funny.
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Yes, he did and "Occupational health hazards of petrol" is fine as a translation.

I was making the point that this paragraph specifically deals with the hazards in refineries rather than in all environments
I agree. Thank you Alan.